The present invention relates to rubber shaping machines, and more particularly to rubber injecting and vulcanizing shaping machines.
The conventional rubber shaping machine, as shown in FIG. 1, normally includes an upper mold B mounted on a mold frame, a lower mold A vertically and movably mounted under the upper mold and an oil cylinder C for vertically moving the lower mold. Such a machine, however, usually has the following disadvantages:
(1) The piston rod of the oil cylinder withdraws to open the mold at the same low speed at which it rises to close the mold. However, a low retreating speed of the piston rod is unnecessary for the mold to function properly.
(2) The shaped piece cannot easily be taken off the mold merely through the disengagement of the upper and lower molds since it is made of elastic material.
(3) Such a shaping machine has an injection band which is apt to spill the rubber material.
(4) Such a shaping machine cannot be properly heated and cooled, causing trouble in cleaning the material.
There is therefore a need to avoid the above problems.